Ability to add custom open dialog for split editor area empty widget.
Ability to add custom open dialog for split editor area empty widget.

Applications need ability to open custom open dialogs (easier than
writing the entire empty_widget), since the editor area does not
know the directory to default to and the file filters to attach
to the dialog.

geggo/pyface,geggo/pyface,brett-patterson/pyface,pankajp/pyface